Transition Elements and Ligands Flashcards

1
Q

What are the electron configurations for Chromium and Copper?

A
  • Cr - 1s2, 2s2, 2p6, 3s2, 3p6, 3d5, 4s1

- Cu - 1s2, 2s2, 2p6, 3s2, 3p6, 3d10, 4s1

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2
Q

Why are the electron configurations for copper and chromium different?

A

Half-filled 3d and 4s sub-shells are more stable than partially filled

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3
Q

Physical properties of transition metals? (3)

A
  • High MP and BP
  • Conducts heat and electricity
  • Used for construction, cables, pipes etc.
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4
Q

Properties of transition metal compounds? (3)

A
  • Form coloured compounds
  • Act as catalysts (due to variable oxidation states)
  • Same element can have different oxidation state depending on the compound
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5
Q

What are the oxidation states and colours for Titanium? (1)

A

+3 = lilac

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6
Q

What are the oxidation states and colours of Vanadium? (4)

A
\+2 = lilac
\+3 = green
\+4 = blue
\+5 = yellow
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7
Q

What are the oxidation states and colours of Chromium? (3)

A
\+2 = blue
\+3 = green
\+6 = orange
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8
Q

What are the oxidation states and colours for Manganese? (4)

A
\+2 = pale pink
\+4 = brown
\+6 = green
\+7 = violet
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9
Q

What are the oxidation states and colours for Iron? (2)

A
\+2 = pale green
\+3 = pale yellow
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10
Q

Wha are the oxidation states and colours for cobalt? (2)

A
\+2 = pink 
\+3 = green
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11
Q

What are the oxidation states and colours of Nickel? (1)

A

+2 = green

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12
Q

What are the colours and oxidation states of copper? (1)

A

+3 = blue

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13
Q

What are catalysts?

A

Substances that provide an alternate pathway with a lower activation energy

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14
Q

Why are transition metals good catalysts? (2)

A
  • Transfer electrons easily

- Provide a site to react - reactants can be held in place by adsorption and are released by desorption

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15
Q

What are some examples of reactions where a transition metal acts as a heterogeneous catalyst? (4)

A
  • Haber process - Fe2+ catalyst
  • Contact process - V2O5 catalyst
  • Hydrogenation of alkenes - Ni
  • Decomposition of hydrogen peroxide - MnO2-
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16
Q

What is an example of a reaction where a transition element acts a homogeneous catalyst?

A

Fe 2+ catalyses the reaction between iodide and peroxidisulphate, S2O8 2-

17
Q

What is the definition of a complex ion?

A

Transition metal ion bonded to one or more ligands by a coordinate bond

18
Q

What is the definition of a ligand?

A

A molecule or ion that can donate a pair of electrons with the transition metal ion to form a coordinate bond

19
Q

What is the definition of a coordinate bond?

A

When one of the bonded atoms provides both electrons to the bond. Also known as a dative covalent bond

20
Q

What is meant by coordination number?

A

Number of coordinate bonds attached to the central metal ion

21
Q

What is meant by a mono-dentate ligand?

A

A ligand that forms 1 coordinate bond per ligand with the central metal ion

22
Q

What are some examples of mono-dentate ligands? (6)

A
  • H2O:
  • :NH3
  • :SCN (-1)
  • :CN (-1)
  • :Cl (-1)
  • :OH (-1)
23
Q

What is meant by a bi-dentate ligand?

A

Donates 2 pairs of electrons and forms 2 coordinate bonds with the central metal ion

24
Q

What are some examples of bi-dentate ligands? (3)

A
  • Ethane-1,2-diamine -> :NH2 - CH2 - CH2 - :NH2 (no overall charge)
  • Ethandioate -> :O - C(=O) - C(=O) - O: (-2 charge)
  • Ketones (no overall charge)
25
Q

What is meant by a multi-dentate ligand? Example?

A

A ligand that donates 3 or more electron pairs and forms 3 or more coordinate bonds
e.g. EDTA (6 coordinate bonds)

26
Q

What is EDTA used for? (5)

A
  • Bind to metals to lower conc.
  • Used in detergents to soften water
  • Bind to metal in food to slow oxidation
  • Added to blood to prevent clotting
  • Treat mercury poisoning
27
Q

What shape do 6 coordinate no. complex ions form?

A

Octahedreal

28
Q

What shape does a 4 coordinate no. complex ion form? What are the exceptions?

A
  • Tetrahedral

- Pt 2+, Pd 2+ and Au 3+ are exceptions - form square planar

29
Q

What are the conditions for an optical isomer? How would you draw one? (3)

A
  • Coordination no. of 6
  • Octahedral
  • With 2 or more bi-dentate ligands
30
Q

How are complex ions used in medicine? (5)

A
  • Cis Platin [PtCl2(NH3)2] was a drug used for cancer
  • Binds to DNA of fast growing cancer cell - prevents from replicating
  • Cells own repair system leads to death of cells
  • Basis for chemotherapy and has side effects
  • Newer treatments involve carboplatin as it has fewer side effects and lower doses can be used
31
Q

What is a ligand substitution reaction?

A

When one ligand in a complex ion is replaced with another

32
Q

Why do some ligands get displaced?

A

Other ligands have a combine more strongly with the transition metal

33
Q

What is the colour change and equation for the reaction of Cu 2+ with OH-?

A

Cu 2+ (aq) + 2OH- (aq) -> Cu(OH)2 (s)

Pale blue solution -> light blue ppt.